THE NERVOUS SYSTEM 313 Chimpanzee Gorilla Superficial Plexus (S.C.P.) Supei jlcial Plexus 1. Cardiac branch of left i 1. Cardiac branch vagus Deep Plexus (D.C.P.) 1. Filaments from left j 1 sympathetic 2. Thoracic branch of left vagus 2. 3. Cervical branch of right vagus 4. Thoracic branches of right vagus 5. Branches from right cervical sympathetic 6. Branch from left recur- rent laryngeal nerve of left vagus Deep Plexus Filaments from right sympathetic Branches o f right vagus Branch from the left recurrent nerve Man Superficial Plexus 1. Upper left cardiac sympathetic nerve 2. Lower cervical car- diac branch of left vagus Ueep Plexus 1. All cervical cardiac branches of sympathetic except the upper left branch 2. All cardiac branches of the vagi except the lower left cervical one 3. Branches of both recurrent nerves The superficial plexus is placed as in Man, but the deep plexus is higher up about the innominate artery. In Man the conditions, particularly the sympathetic contributions to the plexuses, are more complex. In the Apes, as in many lower mammals, the vagus probably conveys many sympathetic filaments. The anterior pulmonary plexuses are formed by branches of the vagus nerves, and the posterior pulmonary plexuses are formed by twigs from the vagus nerves and upper thoracic sympathetic ganglia. Solar Plexus,—In the Chimpanzee (fig. 53) the annular left cceliac ganglion receives the greater part of the right vagus nerve, and each coeliac ganglion receives a great splanchnic nerve. The two ganglia are united by communicating filaments ; and the plexus gives off the following plexuses :— 1. Communicating to the gangliated sympathetic cords (A.GLC.).